Preformed acoustic unit



May 29, 1928.

M. c. RosENBLATT ET Al.

PREFORMED ACOUSTIC UNIT Filed Nov. 50, 1926 'llll/llllllllllll. 'l/ll//l/I. 'll/ll val/6.5'.

m W E y w W/TNESS.

Patented May 29, 1928.

lulvrrao STATES PATENT OFFICE.

MAURICE C. ROSENBLATT, OF PHILADELPHIA, PENNSYLVANIA, AND STANLEY E. ROSENBLATT, 0F ATLANTIC CITY, NEW JERSEY.

PREFORMED ACOUSTIC UNIT.

Application led .November 30, 1926. Serial No. 151,769.

This invention relates to pre-formed acoustic units, and the assembly and mergence of a plurality of units into a unitary acoustic surface.t

Among the objects of the invention are; to provide an acoustic treatment eciency as to sound absorption; vide an acoustic treatment as a series of pre formed units; to provide a`series of preformed units arranged for association on a to prosurface to be acoustically treated; to provide an acoustic treatment in which there is an absence of visible seams; to provide an acoustic treatment in the use of which lath and plaster may be eliminated either in Whole or in part; to provide an acoustic treatment applicable to any surface of a building structure; to provide a series of pre-formed acoustic units applicable to a surface by mechanical fastening devices; to provide an acoustic treatment of such formation as to be applied to a desired surface Without the use of highly trained operators; to provide an acoustic treatment which acts as a seal against the infiltration of dust; to provide an acoustic treatment effective as a -fire barrief as well as a heat insulator; to provide anracoustic treatment having a visual effect as of rough plaster which is comportable with most architectural schemes;

and many other objects and advantages as will be more apparent as the description proceeds. g

As will more clearly appear hereafter,the acoustic treatment of this invention can be applied to I'any surface of a building structure, whether finished orunfinished, Whether Ahorizontal or vertical, and to any material `formin such surface. i The invention in the preferred form comprises a backing layer of material, a layer of felt mounted thereon, and a membrane in intimate engagement with the felt having projecting lapsat desired edges to` overlap with the adjacent unit. In the accompanying drawings, Fig. 1,

. represents .a fragmentary bottom or re- `8 inclusive are details of of high but prior to the final over-lapping engagement of the respective flaps, and Figs. 3 to the invention. Each unit of a series has a backing or backing layer 11, formed preferably of a semi-rigid composition such as to impart rigidity to the entire unit, but which may yield as occasion demands, such for instance as in its application to a curved surface.

The range of materials of which the back.

ing may be formed is ratherwide and the particular layer used should be chosen with the requirements of a particular situation as a consideration. Generally however the backing strip should be but slightly flexible, should preferably be solid With plane surfaces, and it is preferred that it be one of the various types of composition materials available to the public. It may be of an asbestos composition when itis desired to effect a fire barrier, as for instance Where the surfaceto which 'it is a plied omits the coat of plaster, so that in eect the backing will take the place of the fire resistant plaster. It may be a composition or other board of conventional construction if the surface to be treated is one which requires a seal to prevent the infiltration of dust, or insulation against the transmission of heat, or air,

'as where the surface is mere studding,

ciation with they backing strip, as later described, as Well as affording a surface which forms a perfect bond With such plaster.l

These attributes are, of course, of value in applying paste for the felt.

.Assuming the desirability of a particular board to be known, desired lengths or sections thereof are provided, and to each section a layer of felt 12 is attached, which is of the same area as the section of the backplaster of Paris when that is used in assofelt, as by f paintedv or decorated 'as may be. found most pensates ing and with the same angular outline, so thatthe side andmend edges of the backing and of the felt'are in registry substantially perpendicular to the plane of the surface of the backing. The felt is applied to the backing in any desired manner, as by paste, glueI or cement. I

To the exposed surface of the felt 12, a` membrane 13 is attached, as by paste,'glue or cement, in intimate association with the the process known as squee-gee, with an end and side of the. membrane in re istry with the perpendicular end 14 and si e 15 of the' unit, but with an end 16 and side 17 projecting beyond the registering ed es of the felt and backing beneath them, an preferably the projecting portions of the flaps terminate in an uneven, ravelled or frayed' 'edge l18. This unevenness'v is easily attained by the severance of the 'selvage of the membrane from the main body thereof, the edge of the aps being thus uneven 'a blending effect is'had With-the surface upon which it ,is later overlapped. The membrane is preferably ofa 'loosely woven material, such as gauze,cotton sheeting, burlap, etc., and which is the exposed element of the unit, which can later be desirable.

Felt yis so far as known, the most efficient sound absorbing medium available .in the art, but it is difficult to handle due to its usually extreme pliabilityv and lack of c o- A hesion, and is of an uncompromising appearance. A membrane in contact with the felt, if of such porosity as to permit the passage of sound waves enhances the absorption of the felt by its own degree of absorption, or substantially so. This comsomewhat for the necessity for a limitv on the thickness of felt that can bev used, as, although there is a higher absorption with the thicker felt, generally, yet,y due to the inherent weakness of the felt such thickness as gives4 the utmost efficiency Y, can tear i itself apart of its own weight. Thus in practice, the ideal thickness of felt.

v .as

for the utmost of`.absorption cannot be,

,availed of, and thinner felt must be used.

This latter also because .of the cost of the felt. As noted there is some compensation I for this-loss of `eiiicieneyv but the Vassembly vis still short of that is, of total absorption. part to the transmission of membrane, perfection, Thls 1s due 1n sound through the assembled membrane and felt to the surface upon whichfthey are mounted, and the reflection of such transmitted waves face is highly reiective the absorption is .lower than if it is not relietive. Therefore, by forming the backinglayer of sound absorbing material it has been possible to provide' a unit of backing, felt, and memby the use of the from the surface.` If the sur? `brane, which all function Iin the absorption v of sound, with a consequence of maximum absorption with, such unit. This is to be understood as clearly `differentiating 'from the assembly of a fibrous porous board and felt disclosed in the Patent #1,609,311, to Maurice C. Rosenblatt, ,asv in that patent, the/board,- being exposed did not transmit the felt therein functioning asa vibration damper, and not as a sound absorber.

It is contemplated `that the units so' are not slots nor openings but a division ofl the fibers so that the edges may be separated to admit a fastening device such as a screw or toggle bolt. In application in the latter case the unit is held against the surface in any desired manner, and holes are/punched `any sound/waves tothe inner layer of felt,

through the surface in registry with the apertures, using' the 'slits and apertures as guides, and'through which toggle bolts 22,

- -having washers 23 maybe passed to abut the felt side of the backing with the link 24 of the toggle in engagement with the inner' side of the engaged surface.

In some cases it may be desirable to provide the rear faces of the backing with spring clips 25, such as will pass through metal lath and resiliently engage portions thereof, in order .to maintain the units in their operative position.

Some surface'shave a tile or similarinner construction surfaced with a layer of plaster, to which'units of this invention may be applied by the previous attachment of a heyl 26 to the rear face .of thebacking. The'key may be a small section of metal lath, nails, screws, etc., as may bey convenient.' A section of the original plaster is chiseled out or otherwise removed, as at 27, in `registry with the key of the unit to be applied -thereover, which recess thus formed is filled with plaster of Paris into which thekey of the unit ispressed. The setting of the plaster of Paris firmly anchors the unity byv means of the keys. Such devices as the plaster ofy Paris plug 'may be used without any key if the unit includes, as a backing the particular type of porous fibrous substantially water-proof composition material exemplified by certain materials now before the public, as the plastersecures a rm grip on the surface, and due to its nature there is no absorption of the water of theplaster,

and firm anchoring of the backing and umt is had when the plaster of Paris sets. For this method of attachment it will be understoodl that the plug of plaster of Paris projects slightly from the adjacent surface in which it is embedded, so as to be abutted by the re-inforcing layer ofthe acoustic unit. (Not sho-Wn).

After their attachment in any desired manner or as disclosed, each unit is attached to the surface, with the adjacent unit in abutting engagement with the perpendicular edge, theV free edge of one unit abuttinglthe iiap carrying edge of another, being applied serially or successively to the surface. As first applied the flap projections hang freely from the units. The edges of the slits, if any have been formed, are drawn together, and if neces-sary a little hair or felt is smeared with 'paste and rolled or` worked into the slits to preserve the uniformity vof the surface, as it is also inserted into whatever spaces or gaps there might be between adjacent units. Then the flaps of each unit are combed out, smeared with paste, etc., and squee-geed into substantially invisible asso'- ciation with the adjacent units, over the joints between the units.

In using the invention it is the practice to pre-form a series of units at a desirable location, asin a factory or shop, and to transport a desired number to the work. Ob.-

viously they might be formed at the work but apart from it, to be subsequently at tached as units. The operators necessary for the mere attachment of the units need not be highly skilled, and it will be clear that if the area to be covered is not an exact multiple of the units, one or more units may be sawed or cut by the operators to fill in the odd areas. The acoustic surface thus created is one of high sound absorptive value, and of attractive` ap earance, of itself, and 7further Which can. e decorated at will. e

7e claim as our invention:

1. The combination with a surface to be treated, of a plurality of acoustic units asso? ciated therewith in" abutting relation, each unit comprising a backing board, a felt layer and amembrane, and means engaged beface, of a sealing acoustic treatment connected thereto including a relatively slitl internal layer of composition material, an intermediate imposed layer of felt in intimate contacting association with said internal layer, and an external exposed membrane in intimate contacting association with the layer of felt.

3. The combination with a surface to be treated, of an acoustic manipulatable unit, said unit comprising a layer of reinforcing composition material arranged for associationWith mechanical fasteners, mechanical fasteners interposed between the layer and said surface, 'a layer of sound absorbing material mounted on the re-inforcing material, and a woven membrane imposed upon the last mentioned layer and susceptible to decoration.

4. The combination with a structural element of a bui1ding,'of an acoustic treatment connected therewith, comprising a layer of composition material having a relatively high co-efticient of sound absorption in juxtaposition to said element, an intermediate layer of sound absorbing felt attached thereto in intimate connecting association theref with, and an external exposed layer of sound absorbing membrane attached to and in intimate contacting association with said felt.

5. The combination with a structural element of a building, of an acoustic treatment applied thereto and comprising an inner reinforcing layer having mechanical fastening devices mounted thereon for engagement with the element, and an outer acoustic assembly having a high co-eiiicient of sound absorption mounted on said inner re-inforcing layer.

In testimony whereof We affix our signatures.

MAURICE C. ROSENBLATT. STANLEY H. ROSEN BLATT. 

